Cam chain question

I picked up a wr 426 in march of this year. When I first rode it, this bike would do 3rd gear roll on wheelies with ease. I notice the engine was quite noisie so I order a cam chain and installed it and checked the valves. The old cam chain was stretched real bad ,worst I have ever seen and surprise it didn't break. The engine also has a a Wiesco 13 to 1 piston in it and a decompression cam. After I put it back together the bike will not do 3rd gear wheelies as easy as before. The bike feels like my other wr400 and my yz426'. I am not saying its slow, It has just lost that little extra it had. Now could it be that the stretched chain gave me a better cam separation that enhanced the power? If I get an adjustable intake and play with the lobe separation I can find that lost power? Exracer2

I picked up a wr 426 in march of this year. When I first rode it, this bike would do 3rd gear roll on wheelies with ease. I notice the engine was quite noisie so I order a cam chain and installed it and checked the valves. The old cam chain was stretched real bad ,worst I have ever seen and surprise it didn't break. The engine also has a a Wiesco 13 to 1 piston in it and a decompression cam. After I put it back together the bike will not do 3rd gear wheelies as easy as before. The bike feels like my other wr400 and my yz426'. I am not saying its slow, It has just lost that little extra it had. Now could it be that the stretched chain gave me a better cam separation that enhanced the power? If I get an adjustable intake and play with the lobe separation I can find that lost power? Exracer2

Are you running pump gas? 13/1 is stretching it on pump gas and it may have had high octane stuff in it from previous owner on your first ride.

If it doesn't ping, octane isn't a problem.

The decomp cam you bought, was that for a WR or a YZ426?

It did not have race gas and the cam was already in it. I just put a new cam chain in it. It will ping if I lug it but other wise it runs good, starts and idles great. It does warm up faster then my other bikes. It usually runs about 160 to 180 degrees. Exracer2

Your exhaust cam timing is off by one tooth (too close)

It's 13 pins and timing is set to hot cam marks.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now